Here is the full list of all 45 Blasphemous achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Provoke the meeting between Redento and Cleofás.
Cross the Bridge door in less than 3 hours.
Unlock the ending A.
Get 100% of the game.
Achieve the maximum value of flasks.
Achieve the maximum value of rosary bead slots.
Get all rosary beads.
Beat all the arena challenges.
Talk with all the corpses.
Get all collectibles.
Get all prayers.
Achieve the maximum value of fervor.
Get all sword hearts.
Release all cherubs.
Buy all skills from the Mea Culpa shrines.
Unlock the ending B.
Beat His Holiness Escribar.
Beat all bosses without flask consumption.
Discover all zones.
Beat Crisanta of the Anointed Blade.
Beat all types of enemies.
Help Cleofás in his path of redemption.
Achieve the maximum level of the Mea Culpa sword.
Achieve the maximum value of health.
Get all relics.
Bring all the offerings to Lvdovico.
Bring all the offerings to the Blessed Lord of Salty Shores.
Help the Pilgrim reach his final destination.
Save all Kissers of Wounds.
Witness the last moments of Viridiana.
Beat Melquíades, The Exhumed Archbishop.
Use the Righteous Riposte 5 times.
Beat Quirce, Returned by the Flames.
Execute 5 different enemies.
Buy all the items of the Candelaria shops.
Beat Exposito, Scion of Abjuration.
Beat Esdras, of the Anointed Legion.
Hatch the Egg of Altasgracias.
Beat the Tres Angustias.
Visit the tomb of The Lady of the Tailed Gown.
Kill 666 enemies.
Beat Perpetua.
Beat Ten Piedad.
Beat the Our Lady of the Charred Visage.
Beat the Warden of the Silent Sorrow.